Well, that really looks pretty clever!
Is the heat shrink in 1 piece from wheel axle over dogbone to the diff cup? No, looking a your photos that's impossible, so it's in 3 pieces on each side if I see it well?
You are right, it is the slop between the pin and the slot that causes the premature wear, that's why this time I'm gonna replace the whole shebang instead of just the diff cups.
If you can manage to fit thicker pins in the dogbones, make a how-to, I'll be glad to see how you manage that!